From the safety position the blade support can also be moved into a blade-change position in which the blade projects out of the casing to a greater extent than in the cutting position. In the blade-change position the blade can be for example partially or completely out of the casing. From the cutting position or the blade-change position the blade support can be moved back into the safety position. The knife according to the invention comprises an actuator. The blade support can be moved with the actuator. A handle is part of the actuator. The handle is operated by the user to move the blade support. Such a knife is known from the prior art.